Changing Bitcask Expiry Policy

Felipe Esteves felipe.esteves at b2wdigital.com
Thu Jun 29 10:29:11 EDT 2017


Thanks a lot for this brief explanation, Martin!

Felipe Esteves

Tecnologia

felipe.esteves at b2wdigital.com <seu.email at b2wdigital.com>

Tel.: (21) 3504-7162 ramal 57162

Skype: felipe2esteves

2017-06-27 13:55 GMT-03:00 Martin Sumner <martin.sumner at adaptip.co.uk>:

> Felipe,
>
> I've not played around with this myself.  However, after a brief look at
> the bitcask code, it looks like a timestamp is given to each object as it
> is written to bitcask - to represent the time it was written, not the time
> it will expire.  The expiry_time is part of the state of the bitcask
> process passed on startup, and is not looked at during the PUT flow.
>
> Bitcask checks to see if an object is expired when it is read (and also
> when merging files), by comparing the write_time timestamp with the current
> time (less the expiry time in seconds) - and the object is then deleted as
> part of the GET operation.  So if the expiry time is disabled, these reads
> will be forever valid once bitcask has that new state, as no knowledge of
> the old expiry time is retained in the store. I don't think the object
> itself has any sense of when it will expire, so I would expect that in your
> case your data will be preserved.
>
> I would recommend testing this before relying on my quick read through.
>
> Regards
>
> Martin
>
> Hi,
>
> any hint on this question?
>
> Felipe Esteves
>
> Tecnologia
> felipe.esteves at b2wdigital.com <http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com> <seu.email at b2wdigital.com <http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com>>
>
> Tel.: (21) 3504-7162 ramal 57162
>
> Skype: felipe2esteves
>
> 2017-06-21 16:35 GMT-03:00 Felipe Esteves <felipe.esteves at b2wdigital.com <http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com>>:
>
> >* Hi,
> *>>* If I have a Riak cluster with bitcask expiry turned on, let's say, 14
> *>* days, and then change it to *bitcask.expiry=off* before any expiration
> *>* occurs, all my data will be preserved? Or all data prior to the parameter
> *>* change could still expiries based on the previous deadline?
> *>>* Riak is version 2.2.3
> *>>* thanks,
> *>>* Felipe Esteves
> *>>* Tecnologia
> *>>* felipe.esteves at b2wdigital.com <http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com> <seu.email at b2wdigital.com <http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com>>
> *>>>
>
>
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